clues to the cover?

[theadimail]

No: HPFGUIDX 131929

hi,
 I was just browsing through the first book and something hagrid said 
caught my eye. Introducing Leaky to harry , he says it's a famous 
place. Why is it famous? There are after all other bars in winzarding 
world. So why should this dingy bar be famouse? And is it  a small 
coincidence that the cover of the HBP fatures something that looks 
like a cauldron that is leaking?
Bye
Adi